Cholesterol-phospholipid interaction in membranes. 2. Stoichiometry and molecular packing of cholesterol-rich domains

摘要: A model for the molecular interaction between cholesterol and phospholipid in bilayer membranes is presented. We propose that forms associations with phospholipids stoichiometries of both 1:1 1:2. hydrogen bond beta-OH glycerol ester oxygen a suggested as likely mechanism tight binding complex. second molecule loosely associated complex to form domains 1:2 stoichiometry, which may coexist pure domains. Interfacial boundary separates these two Under conditions interfacial maximal, perturbed assumes composition 20 mol % cholesterol. To account phase behavior surface properties cholesterol-lipid membranes, we packing linear arrays within cholesterol-rich In this arrangement, rows run antiparallel intercalated them. The can pack nearly hexagonal manner crystalline known pack. provides maximal van der Waals contact hydrocarbon region maintain cholesterol's nearest neighbors at all concentrations up 50 compatible diverse experimental observations compiled by many investigators over past decade.